Half to thomas gorman



(No Model.) I 2 Sheets-Sheet 1. D. DUNN.

, AIR BRAKE FOR RAILWAY CARS. No. 431,938. Patented July 8, 189(1).

I Wyn 93% d I (No Model.) 2 Sheets-Sheet 2. D. DUNN.

AIR BRAKE FOR RAILWAY CARS.

.No. 431 988. Patented July 8, 1890.

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UNITED 1 STATES PATENT OF ICE.

DENNIS DUNN, OF MAHANOY CITY, PENNSYLVANIA, ASSIGNOR OF ONE- HALF TO THOMAS GORMAN, OF SAME PLACE.

Al R-BRAKE FOR RAl LWAY-CARS.

SPECIFICATION forming part of Letters Patent No. 431,938, dated July 8, 1890.

Application filed May 12, 1890. Serial No. 351,493- (No model.)

To aZZ whom it may concern.-

Be it known that I, DENNIs DUNN, a citizen of the United States, and a resident of Mahanoy City, in the county of Schuylkill and State of Pennsylvania, have invented certain new and useful Improvements in Air-Brakes for Railway-Cars; and I do hereby declare that the following is a full, clear, and exact description of the invent-ion, which will enable othersskilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification.

My invention relates to improvements in air-brakes for railroadand other cars, the obect being to provide simple and effective means for compressing the air and supplying it to the brake mechanism.

The invention consists in the novel construction and combination of parts hereinafter fully described, and definitely pointed out in the claims.

In the accompanying drawings, Figure 1 represents a side elevation of my improved compressing and braking device applied to a car. Fig. 2 is a plan view of the same. Fig. 3 is a detail sectional view of the air-reservoir and liquid-receptacle. Fig. 4 is a similar view of-the air-compressor. Fig. 5 is a detail view of the three-way cock.

In the said drawings, the reference-numeral 1 designates the platform of a car, and 2 the wheels.

Secured to the axle 3 of one pair of wheels is a cog-wheel 4, which meshes with a similar wheel 5, mounted in brackets 6, depending from the bottom of the car.

7 designates the air-compressor bolted or otherwise connected with the car-bottom. It consists of a cylinder 8, within which works a piston 9, connected by means of pistoirrod 10 and connecting-rod 12 and crank-pin 13 with the cog-wheel 5.

At each end of the cylinder 8 are secured the entrance and exit pipes 14 and 15, the pipe 14: being open to the air, and pipe 15 connecting by pipe 16 with the reservoir 17. In each of these pipes 14 and 15 are located check-valves 18 18 18 18, which are so arranged that while one is open the other is closed-that is to say, when the piston is traveling in the cylinder in the direction indicated by the arrow valves 18 and 18 will be closed and valves 18 and 18 will be open. The air compressed in the cylinder will then escape through valve 18 and be conducted to reservoir 17 by'means of pipe 16. A safetyvalve should be connected with pipe 16, so that when the pressure shall have reached a certain point it will open and allow the air to escape, as will be understood by those skilled in the art. This air-reservoir is secured to the car in any convenient manner and communicates by means of pipe 19 with a liquid vessel or receptacle 20, containing glycerine or other suitable liquid, which is forced by the compressed air to the piston-cylinder which operates the brake, as will be hereinafter described. Connected with pipe 19 is a three-way cook 21, so constructed and arranged that when turned one way communication will be established between the reservoir 17 and vessel 20, and when turned the other way to shut off communication there between it will communicate'with the atmosphere.

The numeral 22 designates a pipe leading from near the bottom of vessel to the brake-cylinder 23, having piston 24. The piston-rod 25of piston 24 is connected with rectangular-frame 26, which in turn is connected with rod 27, connected with the pivoted brake-levers 28, carrying the brakeshoes 29. Secured to this frame are springs 30, the tendency of which is to throw the brake-shoe out of contact with the wheels. The cook 21 is connected with a lever or other device by which it may be operated to set the brakes.

The operation is as follows: WVhen the cars are started, the Wheels actuate the piston 9 by means of the cog-wheels and connections. This will cause the air to be compressed and stored in the reservoir 17 until wanted for use. The safety-valve will prevent too great a pressure being attained. WVhen in normal condition, the three-way cock will close communication between reservoir 17 and vessel 20. WVhen, however, it is desired to apply the brakes, the cook 21 is turned so as to open communication between reservoir 17 and vessel 20 and cut ofi communication with the open air. The compressed air will now rush to vessel 20, and acting upon the liquid contained therein will force said liquid through pipe 22 to the cylinder 23, causing the piston therein to be actuated and the brakes applied through the connections therewith. When it is desired to release the brakes, the three- Way cock is operated to shut off communication between reservoir-'17 and vessel 20 and open communication from vessel 20 with the open air, when the springs 30 will cause the piston to be operated in a reverse direction and the brake to be retracted.

Having thus described my invention, what I claim is- 1. A mechanism for operating air-brakes, consisting of an air-compressor actuated by the car-axles, a reservoir connected with the air-compressor, a liquid-vessel, a pipe having a three-way cock connecting said reservoir and vessel, a brake-cylinder having piston connected with the brakes, and a pipe connecting the brake-cylinder and liquid-reservoir, substantially as described.

2. Ina mechanism for operating air-brakes, the combination of an air-compressor, a reservoir, a liquid-vessel, a pipe connecting said reservoir and liquid-vessel provided with a three-way cook, a pipe leading from the bottom of said vessel to the brake-cylinder, a piston in the brake-cylinder, a pistod-rod connected with a frame for setting the brakes, and springs for retracting the brakes, substantially as described.

In testimony that I claim the foregoing as my own I have hereunto afiixed my signature in presence of two witnesses.

DENNIS DUNN. \Vitnesses:

M. J. OAUGHNEY, THos. F. GORMAN. 

